1. Field of the Invention
The present invention relates to improving the properties of phenol-containing streams, such as coal liquids and petroleum asphaltenes, by oxygen-alkylation. The resulting upgraded stream has improved storage and processing properties.
2. Description of the Prior Art
The viscosity of phenol-containing hydrocarbonaceous streams such as coal liquids and petroleum asphaltenes generally increases with time, thereby presenting problems in the storage and use of such liquids. Many of these liquids are rich in heteroatoms, and especially organic oxygen such as phenolic oxygen and carboxylic oxygen. It is believed that increases in molecular weight and consequently in viscosities are brought about in two ways: (1) by hydrogen bond formation and (2) by free radical initiated growth reactions.
Furthermore, because streams such as coal liquids are generally rich in phenolic and other polar functionality, they are not fully misible with petroleum liquids of comparable boiling point range which are usually less polar. Segregation of such streams can occur if mixed because the petroleum liquids, which generally lack highly polar groups, cannot participate in the intermolecular association between adjacent coal liquid molecules.
Although various methods have been proposed to eliminate or at least alleviate the aforementioned problems, there is still a need to develop more efficient and economical ways of improving properties such as the stability of such liquids.